Final Exam Material

Question 1

gestation length of a mare is

Answer 1

340 +/- 20 days

Question 2

how does day length affect breeding

Answer 2

seasonally polyestrus; longest day = June 21st

Come into heat when day length is longer

Question 3

Breeding season cycle

Answer 3

Winter (Anestrus) –> Spring (resurgence) –> Breeding season –> Fall (receding)

Question 4

when is the estrous period/ovulatory season

Answer 4

mid april - end of september

Question 5

physiological season

Answer 5

when mare (&stallion) is most reproductively efficient

Question 6

operational season

Answer 6

people control breeding season to allow us to organize when horses are being bred and lets us pan to have them born as close to jan 1 as possible

Question 7

the period from on e ovulation to a subsequent ovulation

Answer 7

estrous cycle

Question 8

estrous cycle in the mare

Answer 8

21-23 days
5-7 days estrus
14-16 days diestrus

Question 9

period of receptivity

Answer 9

estrus

Question 10

when is ovulation

Answer 10

last 24-48 hours of estrus

Question 11

signs of estrus

Answer 11

attitude towards stallion; stance; raise tail; urination; winking of vulva

Question 12

signs of diestrus

Answer 12

rejection of stallion; kicking; striking; squealing

Question 13

receives environmental signals –> sunlight

Answer 13

pineal gland
melatonin secretion decreases
GnRH secretion increases

Question 14

hypothalamus role in estrous

Answer 14

gonadotropic releasing hormone GnRH

stimulates the anterior pit. gland to release: FSH and LH

Question 15

anterior pituitary releases

Answer 15

FSH and LH

Question 16

FSH

Answer 16

recruit multiple follicles

Question 17

LH

Answer 17

slower to react to sunlight/daylength; affects ovary; follicular maturation; peaks after ovulation; formation of CL

Question 18

what causes regression of the CL

Answer 18

prostaglandin

Question 19

fertilized ova pass to the uterus on day

Answer 19

6

Question 20

formation of the CL

Answer 20

produces progesterone; maternal recognition

Question 21

maternal recognition

Answer 21

persistent CL; day 7-16; conceptus motility; affects PGF2alpha

Question 22

placental forms on day

Answer 22

25

Question 23

chorionic girdle cells

Answer 23

endometrial cups; invades maternal tissue; day 36-40

Question 24

endometrial cups

Answer 24

produce eCG; LH like properties increases day 38-40 and peaks at day 6-=70; maintain progesterone; not detectable after 130 days

Question 25

gestation length is affected by

Answer 25

sex of foal; mares nutritional status; genotype of foal (mules longer); individual mare (maiden vs first timers, etc)

Question 26

anestrus

Answer 26

nov-jan; little ovulation activity; low GnRH

Question 27

spring transition

Answer 27

GnRH increases; build up of LH; delay in ovulation; march 21st

Question 28

PMSG

Answer 28

pregnant mare serum gonadotropin | maintain progesterone

Question 29

normal cycle

Answer 29

4 consecutive days of estrus followed by 8 consecutive days of diestrus

Question 30

teasing mares

Answer 30

one of the most important parts of program

Question 31

teasing mares determines

Answer 31

stage of estrus; pregnancy

Question 32

teasing methods

Answer 32

facilities available; type of mares; # of mares; help available; keep good records; safety issue; time per mare; all mares every day; different places used (stalls, pens, chute)

Question 33

purpose of reproductive management

Answer 33

breed earlier, schedule breeding, enhance preg. rate

Question 34

how to manage reproduction

Answer 34

lights, hormones, and combination of both

Question 35

transitional mare

Answer 35

``` seasonal anestrus-->normal cycle low GnRH pineal gland responds to day length response of hypothalamus is different than pituitary gland GnRH increase is faster LH increase is slower ```

Question 36

light therapy

Answer 36

16 hrs of light start now or dec 60-90 d to first ovulation cant have shadows

Question 37

hormone therapy

Answer 37

progesterone, p & e mixed, regumate (be careful-affects people) post-treatment - use PGF2alpha last treat day

Question 38

late transitional mare

Answer 38

ovarian activity; treat for 12-15 days; 12 days post treat ovulation

Question 39

suppression of estrus

Answer 39

need ovarian activity; prolonging diestrus; progesterone

Question 40

progesterone

Answer 40

maintenance of pregnancy

Question 41

prostaglandin

Answer 41

luteolytic regression of cl

Question 42

sertoli cells

Answer 42

sperm production; support spermatogenesis; under the influence of FSH and Testosterone

Question 43

leydig cells

Answer 43

secrete steroid hormones: mainly test. | influenced by LH

Question 44

epididymis

Answer 44

head, body, tail, maturation of sperm, storage in tail

Question 45

accessory sex glands

Answer 45

ampullae, vesicular glands, prostate, bulbourethral produce seminal plasma

Question 46

Daily sperm production

Answer 46

19-20 million per gram

Question 47

factors affecting daily sperm production

Answer 47

testicular size (changes with age, sexual maturity 6+ years of age) scrotal width, testicular volume, cryptorchidism